There is no effective therapy in patients with depression and Alzheimer’s disease (AD). The need for novel treatments offers researchers the opportunity to explore new technology for these disorders. Transcranial low-level laser therapy (LLLT) is a novel therapeutic approach based on laser irradiation to biological tissue, and it has been used to treat brain disorders. Although there are certain therapeutic options for depression and AD, there is little treatment
available as non-invasive physical therapy. In this mini-review, we focus on a growing body of evidence surrounding the therapeutic effects of LLLT for depression and AD. Transcranial LLLT can enhance ATP biosynthesis, regulate mitochondrial homeostasis, and facilitate neurogenesis and/or neuroplasticity. However, the cellular and molecular mechanisms underlying the treatment of LLLT on these disorders are still at early stages. Clinical trials on depression and AD by transcranial LLLT are critical for future studies.